Cooling system for a data processing unit

ABSTRACT

A data processing unit includes a chassis configured to contain a line card. The chassis defines, at least in part, a portion of a first flow pathway and a portion of a second flow pathway. The chassis is configured such that a first portion of a gas can flow within the first flow pathway between an intake region and the first end portion of the line card such that the first portion of the gas flows across a first end portion of the line card in a first direction. The chassis is configured such that a second portion of the gas can flow within the second flow pathway between the intake region and a second end portion of the line card such that the second portion of the gas flows across the second end portion of the line card in a second direction opposite the first direction.

BACKGROUND

This invention relates to electronic data processing units, and moreparticularly, to apparatus and methods for cooling a data processingunit.

Some known data processing units include multiple circuit boardsconfigured to process and/or transmit electrical signals. Such knowndata processing units can include, for example, routers, switches,servers, storage devices, and/or components included within a coreswitch fabric of a data center. Such known data processing units includecooling systems configured to prevent overheating of the electroniccircuits (e.g., the modules) included on the circuit boards containedtherein. Some known cooling systems are configured to convey cooling airacross the surface of the circuit boards in a single direction (e.g.,from a first side to a second side). In such an arrangement, however,the electronic circuits disposed on or adjacent the second side of thecircuit board are exposed to cooling air that has been heated as aresult of flowing across the electronic circuits disposed on or adjacentthe first side of the circuit board. Similarly stated, with such coolingsystems, the electronic circuits located downstream receive cooling airhaving a higher temperature than that of the cooling air received by theelectronic circuits located upstream.

Some known data processing units use an orthogonal midplaneconfiguration, in which a first set of circuit boards (e.g., line cards)is coupled to the front side of a midplane in a vertical configurationand a second set of circuit boards (e.g., line cards) is coupled to therear side of the midplane in a horizontal configuration. The orthogonalmidplane configuration allows each line card from the first (i.e.,front) set of line cards to be directly connected to each line card fromthe second (i.e., rear) set of line cards, thus eliminating the use ofprinted circuit board signal traces on the midplane to convey thesignals between the cards. The cooling systems of known data processingunits having an orthogonal midplane configuration often cool the rearset of line cards by diverting air flow from cooling channels in thefront part of the chassis that are used to cool the front set of linecards. This arrangement, however, limits the degree to which the rearset of line cards can be cooled independently from the front set of linecards. Additionally, this arrangement can result in the cooling airsupplied to the rear set of line cards having a higher temperature thanthe cooling air supplied to the front set of line cards.

Thus, a need exists for improved apparatus and methods for cooling thecomponents (e.g., the line cards) within a data processing unit havingan orthogonal midplane configuration.

SUMMARY

Data processing units are described herein. In some embodiments, a dataprocessing unit includes a chassis configured to contain a line card.The line card has a first end portion and a second end portion that ismutually exclusive of the first end portion. The chassis defines, atleast in part, a portion of a first flow pathway and a portion of asecond flow pathway. The chassis is configured such that a first portionof a gas can flow within the first flow pathway between a region outsideof the chassis and the first end portion of the line card such that thefirst portion of the gas flows across the first end portion of the linecard in a first direction. The chassis is configured such that a secondportion of the gas can flow within the second flow pathway between theregion outside of the chassis and the second end portion of the linecard such that the second portion of the gas flows across the second endportion of the line card in a second direction. The second direction isopposite the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematic illustration of a data processingunit according to an embodiment.

FIG. 2 is a perspective view schematic illustration of a portion of adata processing unit according to an embodiment.

FIG. 3 is a perspective view schematic illustration of a data processingunit according to an embodiment.

FIG. 4 is a perspective front view of a data processing unit accordingto an embodiment.

FIG. 5 is a perspective rear view of the data processing unit shown inFIG. 4.

FIG. 6 is a perspective cross-sectional view of the data processing unitshown in FIG. 4 taken along line X₂-X₂ of FIG. 5.

FIG. 7 is a perspective cross-sectional view of the data processing unitshown in FIG. 4 taken along line X₃-X₃ shown in FIG. 5.

FIG. 8 is a perspective rear view of the data processing unit shown inFIG. 4 with a portion of the enclosure removed.

FIG. 9 is a perspective cross-sectional view of the data processing unitshown in FIG. 4 taken along line X₁-X₁ shown in FIG. 4.

FIG. 10 is a rear perspective view of a portion of a data processingunit according to an embodiment.

FIG. 11 is a top view of a line card from the data processing unit shownin FIG. 10.

DETAILED DESCRIPTION

Data processing units are described herein. In some embodiments, a dataprocessing unit includes a chassis configured to contain a line card.The line card has a first end portion and a second end portion that ismutually exclusive of the first end portion. The chassis defines, atleast in part, a portion of a first flow pathway and a portion of asecond flow pathway. The portion of the chassis defining the first flowpathway is configured such that a first portion of a gas can flow withinthe first flow pathway between a region outside of the chassis and thefirst end portion of the line card such that the first portion of thegas flows across the first end portion of the line card in a firstdirection. The portion of the chassis defining the second flow pathwayis configured such that a second portion of the gas can flow within thesecond flow pathway between the region outside of the chassis and thesecond end portion of the line card such that the second portion of thegas flows across the second end portion of the line card in a seconddirection. The second direction is opposite the first direction.

In some embodiments, a data processing unit includes a chassisconfigured to contain a line card. The line card has a first endportion, a second end portion and a central portion between the firstend portion and the second end portion. The chassis defines, at least inpart, a portion of a first flow pathway, a portion of a second flowpathway and a portion of a third flow pathway. The portion of thechassis defining the first flow pathway is configured such that a firstportion of a gas can flow within the first flow pathway between anintake region exterior to the chassis and the first end portion of theline card. The portion of the chassis defining the second flow pathwayis configured such that a second portion of the gas can flow within thesecond flow pathway between the intake region and the second end portionof the line card. The portion of the chassis defining the third flowpathway is configured such that the first portion of the gas and thesecond portion of the gas can flow within the third flow pathway betweena location proximate the central portion of the line card and an exhaustregion exterior to the chassis.

In some embodiments, a data processing unit includes a chassis and aline card. In some embodiments, the data processing unit can include oneor more sets of line cards. The line card is disposed within an interiorregion of the chassis. The chassis defines, at least in part, a portionof a first flow pathway. The chassis is configured such that a gas canflow within the first flow pathway between a first region exterior tothe chassis and the interior region of the chassis, and across a surfaceof the line card in a first direction substantially parallel to thesurface of the line card. The chassis and the line card collectivelydefine a portion of a second flow pathway, which can be, for example, anexhaust flow pathway. The chassis and the line card are collectivelyconfigured such that the gas can flow within a portion of the secondflow pathway in a second direction between the interior region of thechassis and a second region exterior to the chassis. The seconddirection is substantially orthogonal to the surface of the line card.The second region exterior to the chassis can be, for example, anexhaust region at the rear portion of the chassis.

In some embodiments, an apparatus includes a line card configured to bedisposed within a chassis of a data processing unit. The line card has asurface upon which an electronic circuit can be mounted. The electroniccircuit can be, for example, any suitable electronic component,communications module or the like. The line card defines a flow pathsuch that a gas can flow substantially orthogonal to the surface of theline card when the line card is disposed within the chassis. In someembodiments, for example, the line card can define a plurality of holesthrough which the gas can flow when the line card is disposed within thechassis.

As used herein the term “data processing unit” refers to any computer,electronic switch, router or the like used to process, transmit and/orconvey electronic signals. A data processing unit can include, forexample, a component included within an electronic communicationsnetwork. In some embodiments, for example, a data processing unit can bea component included within a core switch fabric of a data center. Inother embodiments, a data processing unit can be an access switchlocated at an edge of a data center or a host device (e.g., a server)coupled to the access device. For example, an access switch can belocated on top of a chassis containing several host devices.

The term “parallel” is used herein to describe a relationship betweentwo geometric constructions (e.g., two lines, two planes, a line and aplane, two curved surfaces, a line and a curved surface or the like) inwhich the two geometric constructions are substantially non-intersectingas they extend substantially to infinity. For example, as used herein, aplanar surface (i.e., a two-dimensional surface) is said to be parallelto a line when every point along the line is spaced apart from thenearest portion of the surface by a substantially equal distance. Twogeometric constructions are described herein as being “parallel” or“substantially parallel” to each other when they are nominally parallelto each other, such as for example, when they are parallel to each otherwithin a tolerance. Such tolerances can include, for example,manufacturing tolerances, measurement tolerances or the like.

The terms “perpendicular,” “orthogonal,” and/or “normal” are used hereinto describe a relationship between two geometric constructions (e.g.,two lines, two planes, a line and a plane, two curved surfaces, a lineand a curved surface or the like) in which the two geometricconstructions intersect at an angle of approximately 90 degrees withinat least one plane. For example, as used herein, a line is said to benormal to a curved surface when the line and the curved surfaceintersect at an angle of approximately 90 degrees within a planeproximate to where the line and the curved surface intersect. Twogeometric constructions are described herein as being “orthogonal” or“substantially orthogonal” to each other when they are nominallyorthogonal to each other, such as for example, when they are orthogonalto each other within a tolerance. Such tolerances can include, forexample, manufacturing tolerances, measurement tolerances or the like.

It should be understood that the references to geometric constructionsare for purposes of discussion and illustration. The actual structuresmay differ from geometric ideal due to tolerances and/or other minordeviations from the geometric ideal.

FIG. 1 is a perspective schematic illustration of a data processing unit100 according to an embodiment. The data processing unit 100 includes achassis 110 and a line card 132. Although not shown in FIG. 1, thechassis 110 can also contain additional components associated with theoperation of the data processing unit 100. Such additional componentscan include, for example, power supplies, data transmission cables,cooling fans, and/or the like. The chassis 110 includes an externalenclosure or side wall 112 that defines an internal region 113 of thechassis 110 within which the line card 132 is disposed. Although thefront and top portions of the external side wall 112 are shown in FIG. 1as being transparent for purposes of illustration, the external sidewall 112 substantially surrounds and/or encloses the internal region 113of the chassis 110. In other embodiments, however, the external sidewall 112 can surround only a portion of the internal region 113 of thechassis 110.

The chassis 110 includes a first internal side wall 120 and a secondinternal side wall 122. In some embodiments, the first internal sidewall 120 and/or the second internal side wall 122 can be structuralmembers that include coupling portions (not shown), such as clips,brackets, slots, or the like, configured to retain and/or support theline card 132 and/or any other components housed within the chassis 110.In other embodiments, the first internal side wall 120 and/or the secondinternal side wall 122 can be non-structural members, such as, forexample, thin sheet steel, plastic or the like. Although the firstinternal side wall 120 and the second internal side wall 122 are shownas being substantially planar, in other embodiments, the first internalside wall 120 and the second internal side wall 122 can have anysuitable shape or relative orientation. As described in more detailherein, the external side wall 112 and the first internal side wall 120collectively define a first flow pathway 121. The external side wall 112and the second internal side wall 122 collectively define a second flowpathway 123.

The line card 132 can be any suitable circuit card that can process,transmit and/or convey electronic and/or optical signals. For example,in some embodiments, the line card 132 can include a printed circuitboard populated with one or more electronic circuits (e.g., modules,chips, integrated circuit packages, etc.) configured to perform thefunctions of the data processing unit 100. In some embodiments, forexample, the line card 132 can be configured to convert optical signalsto and from electrical signals. In some embodiments, the line card 132can be configured to transmit multiple signals associated with one ormore data streams to and from other line cards and/or other dataprocessing units (not shown in FIG. 1) within a communications network.

The line card 132 has a first end portion 133, a second end portion 134and a surface 144. The second end portion 134 of the line card 132 isspaced apart from the first end portion 133 of the line card 132.Similarly stated, the second end portion 134 of the line card 132 ismutually exclusive of the first end portion 133 of the line card 132.The first end portion 133 of the line card 132 is coupled to the firstinternal side wall 120. The second end portion 134 of the line card 132is coupled to the second internal side wall 122. The surface 144 of theline card 132 includes a set of electrical circuits 142. The electricalcircuits 142 can be, for example, any printed circuit module or othersuitable component for performing the data processing functions of theline card 132.

As described above, the external side wall 112 and the first internalside wall 120 collectively define a first flow pathway 121. The externalside wall 112 and the second internal side wall 122 collectively definea second flow pathway 123. Similarly stated, the chassis 110 defines thefirst flow pathway 121 and the second flow pathway 123. Although thefirst flow pathway 121 and/or the second flow pathway 123 are shown asbeing defined substantially entirely by the chassis 110 (e.g., by theexternal side wall 112, the first internal side wall 120 and the secondinternal side wall 122) in other embodiments, a chassis can define onlya portion of a first flow pathway and/or a portion of a second flowpathway. In yet other embodiments, a chassis can define, only in part, aportion of a first flow pathway and/or a portion of a second flowpathway. Moreover, although the first flow pathway 121 and the secondflow pathway 123 are shown in FIG. 1 as being separate and/or distinctfrom each other, in other embodiments, a portion of a first flow pathwayand a portion of a second flow pathway can share a common boundary.

The first internal side wall 120 defines an opening 124 proximate thefirst end portion 133 of the line card 132. In this manner, the firstflow pathway 121 extends within the chassis 110 between an intake regionINT exterior to the chassis 110 and the first end portion 133 of theline card 132. More particularly, the chassis 110 is configured suchthat a first portion G₁ of a gas can flow from the intake region INTinto the first flow pathway 121, as shown by the arrow AA in FIG. 1. Thegas can be any suitable gas (e.g., air, nitrogen, or the like) used tocool the electronic circuits 142 and/or the line card 132. The firstportion of the gas G₁ can flow within the first flow pathway 121,between the intake region INT and the line card 132, as shown by thearrow BB in FIG. 1. Moreover, the chassis 110 is configured such thatthe first portion G₁ of the gas can exit the first flow pathway 121 viathe opening 124 and flow across the first end portion 133 of the linecard 132 in a first direction, as shown by the arrow CC in FIG. 1.Similarly stated, the chassis 110 is configured such that the firstportion G₁ of the gas can flow within the first flow pathway 121 betweenthe intake region INT and the first end portion 133 of the line card 132and can flow across the surface 144 of the line card 132 in a firstdirection.

The second internal side wall 122 defines an opening 125 proximate thesecond end portion 134 of the line card 132. In this manner, the secondflow pathway 123 extends within the chassis 110 between the intakeregion INT and the second end portion 134 of the line card 132. Moreparticularly, the chassis 110 is configured such that a second portionG₂ of the gas can flow from the intake region INT into the second flowpathway 123, as shown by the arrow AA′ in FIG. 1. The second portion ofthe gas G₂ can flow within the second flow pathway 123, between theintake region INT and the line card 132, as shown by the arrow BB′ inFIG. 1. Moreover, the chassis 110 is configured such that the secondportion G₂ of the gas can exit the second flow pathway 123 via theopening 125 and flow across the second end portion 134 of the line card132 in a second direction, as shown by the arrow CC′ in FIG. 1. Thesecond direction is opposite the first direction. Similarly stated, thechassis 110 is configured such that the second portion G₂ of the gas canflow within the second flow pathway 123 between the intake region INTand the second end portion 134 of the line card 132 and flow across thesurface 144 of the line card 132 in a second direction opposite thefirst direction.

In this manner, the chassis 110 is configured to convey the gas to thefirst end portion 133 and the second end portion 134 of the line card132 in parallel and/or opposed flow streams. Thus, the temperature ofthe first portion G₁ of the gas as it exits the opening 124 can besubstantially equal to the temperature of the second portion G₂ of thegas as it exits the opening 125. Similarly stated, the temperature ofthe first portion G₁ of the gas as it flows across the electroniccircuits 142 disposed at the first end portion 133 of the line card 132is substantially equal to the temperature of the second portion G₂ ofthe gas as it flows across the electronic circuits 142 disposed at thesecond end portion 134 of the line card 132. In this manner, the portionof the gas used to cool the second end portion 134 of the line card 132is not heated by first being used to cool the first end portion 133 ofthe line card 132, and vice-versa. Thus, the uniformity, efficiencyand/or effectiveness of the cooling system can be improved as comparedto cooling systems in which the air flows across a line card in seriesand/or in a single direction.

In some embodiments, for example, the flow rate of the first portion G₁of the gas can be controlled independent of the flow rate of the secondportion G₂ of the gas. In some embodiments, the temperature of the firstportion G₁ of the gas can be controlled independent of the temperatureof the second portion G₂ of the gas. Moreover, in some embodiments, thechassis can be configured such that the opposing flow streams of thefirst portion G₁ of the gas and the second portion G₂ of the gas producea turbulent flow adjacent at least a portion of the line card 132,thereby improving the cooling efficiency of the cooling system of thechassis 110.

Although the first pathway 121 is shown and described as being an intakeflow pathway (i.e., the first portion G₁ of the gas is shown as flowingfrom the intake region INT to the first end portion 133 of the line card132), in other embodiments, the first pathway 121 can be an exhaust flowpathway (i.e., the first portion G₁ of the gas can flow from the firstend portion 133 of the line card 132 to an exhaust region exterior tothe chassis 110). Similarly, although the second pathway 123 is shownand described as being an intake flow pathway (i.e., the second portionG₁ of the gas is shown as flowing from the intake region INT to thesecond end portion 133 of the line card 132), in other embodiments, thesecond pathway 121 can be an exhaust flow pathway (i.e., the secondportion G₁ of the gas can flow from the second end portion 133 of theline card 132 to an exhaust region exterior to the chassis 110).

Although the first portion G₁ of the gas flowing across the line card132 is shown as having a direction CC substantially opposite thedirection of the second portion G₂ of the gas flowing across the linecard 132. in other embodiments the direction of the flow of the firstportion G₁ of the gas need not be opposite the direction of the flow ofthe second portion G₂ of the gas.

For example, FIG. 2 is a perspective schematic illustration of a portionof a data processing unit 200 according to an embodiment. The dataprocessing unit 200 includes a chassis 210 and a line card 232. Althoughnot shown in FIG. 2, the chassis 210 can also contain additionalcomponents associated with the operation of the data processing unit200. The chassis 210 includes a side wall 212 that defines an internalregion 213 of the chassis 210 within which the line card 232 isdisposed. Although the front and top portions of the side wall 212 areshown in FIG. 2 as being transparent for purposes of illustration, theside wall 212 substantially surrounds and/or encloses the internalregion 213 of the chassis 210.

The line card 232 can be any suitable circuit card that can process,transmit and/or convey electronic and/or optical signals. For example,in some embodiments, the line card 232 can be similar to the line card132 described above. The line card 232 has a first end portion 233, asecond end portion 234 and a central portion 235 therebetween. The firstend portion 233 of the line card 232 and the second end portion 234 ofthe line card 232 are each coupled to the side wall 212. A surface 244of the line card 232 includes a set of electrical circuits 242. Theelectrical circuits 242 can be, for example, any printed circuit moduleor other suitable component for performing the data processing functionsof the line card 232.

The chassis 210 includes a first duct 220 defining a first flow pathway221 and a second duct 222 defining a second flow pathway 223. In thismanner, the chassis 210 defines the first flow pathway 221 and thesecond flow pathway 223. Although the first flow pathway 221 and thesecond flow pathway 223 are shown as being defined substantiallyentirely by the first duct 220 and the second duct 222, respectively, inother embodiments, only a portion of the first flow pathway 221 can bedefined by the first duct 220 and/or only a portion of the second flowpathway 223 can be defined by the second duct 222. In yet otherembodiments, a chassis can define, only in part, a portion of a firstflow pathway and/or a portion of a second flow pathway. For example, insome embodiments, a first flow pathway and/or a second flow pathway canbe collectively defined by multiple structures, such as for example, aduct, a side wall, a portion of the line card 232 or the like. Moreover,although the first flow pathway 221 and the second flow pathway 223 areshown in FIG. 2 as being separate and/or distinct from each other, inother embodiments, a portion of a first flow pathway and a portion of asecond flow pathway can share a common boundary.

The first duct 220 defines openings 224 proximate the first end portion233 of the line card 232. In this manner, the first flow pathway 221extends within the chassis 210 between an intake region INT exterior tothe chassis 210 and the first end portion 233 of the line card 232. Moreparticularly, the chassis 210 is configured such that a first portion G₁of a gas can flow from the intake region INT into the first flow pathway221, as shown by the arrow DD in FIG. 2. The first portion of the gas G₁can flow within the first flow pathway 221 between the intake region INTand the line card 232 such that the first portion G₁ of the gas can exitthe first flow pathway 221 via the openings 224 and flow across thefirst end portion 233 of the line card 232, as shown by the arrows EEand FF in FIG. 2. Similarly stated, the chassis 210 is configured suchthat the first portion G₁ of the gas can flow within the first flowpathway 221 between the intake region INT and the first end portion 233of the line card 232 and can flow across the surface 244 of the linecard 232 from the first end portion 233 of the line card 232.

The second duct 222 defines openings (not shown in FIG. 2) proximate thesecond end portion 234 of the line card 232. In this manner, the secondflow pathway 223 extends within the chassis 210 between the intakeregion INT and the second end portion 234 of the line card 232. Moreparticularly, the chassis 210 is configured such that a second portionG₂ of the gas can flow from the intake region INT into the second flowpathway 223, as shown by the arrow DD′ in FIG. 2. The second portion ofthe gas G₂ can flow within the second flow pathway 223, between theintake region INT and the line card 232 such that the second portion G₂of the gas can exit the second flow pathway 223 via the openings 225 andflow across the second end portion 234 of the line card 232, as shown bythe arrows EE′ and FF′ in FIG. 2. Similarly stated, the chassis 210 isconfigured such that the second portion G₂ of the gas can flow withinthe second flow pathway 223 between the intake region INT and the secondend portion 234 of the line card 232 and can flow across the surface 244of the line card 232 from the second end portion 233 of the line card232.

The rear portion of the side wall 212 defines an opening 207 proximatethe central portion 235 of the line card 232. In this manner, thechassis 210 defines a third flow pathway 226 between a locationproximate the central portion 235 of the line card and an exhaust regionEXH exterior to the chassis 210. Thus, the chassis 210 is configuredsuch that the first portion G₁ of the gas and the second portion G₂ ofthe gas can flow within the third flow pathway 226 between the locationproximate the central portion 235 of the line card 232 and the exhaustregion EXH, as shown by the arrow GG in FIG. 2. Although the third flowpathway 226 is shown as being defined primarily by the rear portion ofthe side wall 212 (e.g., the opening 207), in other embodiments, thechassis 210 can include one or more baffles, ducts and/or internalstructures to define the third flow pathway 226. Although the exhaustregion EXH is shown as being disposed on an opposite end of the chassis210 from the intake region INT, in other embodiments, the exhaust regionEXH and the intake region INT can be located at the same side of thechassis 210.

As described above, this cooling system arrangement allows the intakecooling gas to be conveyed in parallel to the first end portion 233 ofthe line card 232 and the second end portion 234 of the line card 232.Thus, the temperature of the first portion G₁ of the gas as it exits theopenings 224 can be substantially equal to the temperature of the secondportion G₂ of the gas as it exits the openings 225. In this manner,certain of the electronic circuits 242 disposed on the surface 244 ofthe line card 232 can be cooled in parallel and/or via cooling gas thathas not be heated by first being used to cool other of the electroniccircuits 242. Moreover, this arrangement also allows the exhaust gas tobe conveyed from the interior region 213 of the chassis 210 via acentrally located flow pathway (i.e., the third flow pathway 226).

Although the first pathway 221 and the second flow pathway 223 are shownand described as being intake flow pathways, in other embodiments, thefirst pathway 221 and/or the second flow pathway 223 can be exhaust flowpathways. Similarly, although the third pathway 226 is shown anddescribed as being an exhaust flow pathway, in other embodiments, thethird pathway 226 can be an intake flow pathway.

Although the first portion G₁ of the gas flowing across the line card232 is shown as having a direction FF that is not directly opposing thedirection FF′ of the second portion G₂ of the gas flowing across theline card 232, in other embodiments, the flow direction of the firstportion G₁ of the gas flowing across the line card 232 can besubstantially opposite the flow direction of the second portion G₂ ofthe gas flowing across the line card 232. In yet other embodiments, theflow direction of the exhaust flow (i.e., the first portion G₁ of thegas flowing and the second portion G₂ of the gas flowing within thethird flow pathway 226) can be substantially orthogonal to the flowdirection FF of the first portion G₁ of the gas flowing across the linecard 232 and/or the flow direction FF′ of the second portion G₂ of thegas flowing across the line card 232.

Although the first duct 220 and the second duct 222 are shown as beingsubstantially cylindrical, in other embodiments, the first duct 220 andthe second duct 222 can have any suitable shape. Although the chassis210 is shown and described as defining the third flow pathway 226 viathe opening 207, in other embodiments, the chassis 210 can includeadditional structure, such as internal side walls, ducts or the like todefine a portion of the third flow pathway 226.

Although the first flow pathway 221, the second flow pathway 223 and thethird flow pathway 226 is shown as being defined substantially entirelyby the chassis 210 (i.e., the duct 220, the second duct 222, and theside wall 212, respectively), in other embodiments, only a portion ofthe first flow pathway 221, the second flow pathway 223 and/or the thirdflow pathway 226 can be defined by the chassis 210. In yet otherembodiments, a chassis can define, only in part, a portion of a firstflow pathway, a second flow pathway and/or a third flow pathway.Similarly stated, in yet other embodiments, a portion of a first flowpathway, a second flow pathway and/or a third flow pathway can bedefined by a chassis and another component within the data processingunit (e.g., a card, a power supply module, a cable interface or thelike). For example, FIG. 3 is a perspective view of a data processingunit 300 according to an embodiment. The data processing unit 300includes a chassis 310 and a set of line cards 332. Although not shownin FIG. 3, the chassis 310 can also contain additional componentsassociated with the operation of the data processing unit 300.

The chassis 310 includes a side wall 312 that defines an internal region313 of the chassis 310 within which the line cards 332 are disposed.Although the front and top portions of the side wall 312 are shown inFIG. 3 as being transparent for purposes of illustration, the side wall312 substantially surrounds and/or encloses the internal region 313 ofthe chassis 310. The chassis 310 includes an internal side wall 320,which can be a structural member having coupling portions (not shown)configured to retain and/or support the line cards 132. In someembodiments, the coupling portions can be separate members, such asclips, brackets or the like. In other embodiments, the coupling portionscan be monolithically formed with the internal side wall 320, such as,for example, slots, protrusions or the like. Although the internal sidewall 320 is shown as being substantially planar and parallel to aportion of the side wall 312, in other embodiments, the internal sidewall 320 and can have any suitable shape and can be disposed in anyorientation relative to the side wall 312.

The line cards 332 are any suitable circuit card that can process,transmit and/or convey electronic and/or optical signals. For example,in some embodiments, the line cards 332 can be similar to the line card132 described above. A first end 333 of each line card 332 is coupled tothe internal side wall 320 and a second end 334 of each line card 332 iscoupled to the side wall 312 such that the line cards 332 are disposedwithin the interior region 313 of the chassis 310 in a substantiallyparallel arrangement. Similarly stated, the line cards 332 are disposedwithin the chassis 310 such that a surface 344 of each line card 332 issubstantially parallel to the surface 344 of the adjacent line card 332.Although the line cards 332 are disposed within the chassis 310 in asubstantially parallel arrangement, in other embodiments, the line cards332 can be disposed within the chassis 310 in any suitable arrangement.

The second end portion 334 of each line card 332 defines an opening 343.As shown in FIG. 3, the line cards 332 are disposed within the chassis310 such that the opening 343 of each line card 332 is substantiallyaligned with the opening 343 of the adjacent line card 332. In thismanner, as described in more detail below, the line cards 332 and theside wall 312 of the chassis 310 collectively form an exhaust flowpathway 326. A portion of the boundary of the third flow pathway 326 isshown as dotted lines in FIG. 3. Although the exhaust flow pathway 326is shown as being defined primarily by the line cards 332 (e.g., theopenings 343), in other embodiments, the chassis 310 can include one ormore baffles, ducts and/or internal structures to define the exhaustflow pathway 326. Although the openings 343 are shown as beingsubstantially rectangular, in other embodiments, the openings 343 canhave any suitable shape. Although the openings 343 are shown as beingbounded by a portion of the line cards 332 and the side wall 312, inother embodiments, the openings 343 can be bounded entirely by the linecards 332.

The side wall 312 and the internal side wall 320 collectively define anintake flow pathway 321. Similarly stated, the chassis 310 defines theintake flow pathway 321. Although the intake flow pathway 321 is shownas being defined substantially entirely by the chassis 310 (e.g., by theside wall 312 and the internal side wall 320) in other embodiments, achassis can define only a portion of an intake flow pathway. In yetother embodiments, a chassis can define, only in part, a portion of anintake flow pathway. The intake flow pathway 321 extends within thechassis 310 between an intake region INT exterior to the chassis 310 andthe first end portion 333 of each line card 332. More particularly, thechassis 310 is configured such that a gas G can flow from the intakeregion INT into the intake flow pathway 321, as shown by the arrow HH inFIG. 3. The chassis 310 is configured such that the gas G can exit thefirst flow pathway 321 and flow across the surface 344 of each line card332, as shown by the arrows II, KK and MM in FIG. 3. Said another way,the chassis 310 is configured such that the gas G can exit the firstflow pathway 321 and flow in a direction substantially parallel to thesurface 344 of each line card 332. Similarly stated, the chassis 310 isconfigured such that the gas G can flow within the first flow pathway321 between the intake region INT and the first end portion 333 of eachline card 332. In this manner, the chassis 310 is configured to supplythe gas G to cool each of the line cards 332 via a substantiallyparallel flow circuit.

As described above, the chassis 310 and the line cards 332 collectivelydefine an exhaust flow pathway 326 between the second end portion 334 ofeach line card 332 and an exhaust region EXH exterior to the chassis310. Thus, the line cards 332 and the chassis 310 are collectivelyconfigured such that the gas G can flow within the exhaust flow pathway326 from the second end portion 334 of each line card 332, as shown bythe arrows JJ, LL and NN in FIG. 3. Said another way, the line cards 332and the chassis 310 are collectively configured such that the gas G canflow from a region proximate the surface 344 of each line card 332 intothe exhaust flow pathway 326, as shown by the arrows JJ, LL and NN inFIG. 3. Similarly stated, the line cards 332 and the chassis 310 arecollectively configured such that the gas G can flow from the second endportion 334 of the each line card 332 in a direction substantiallyorthogonal to the surface 344 of each line card 332. In this manner, theline cards 332 and the chassis 310 are collectively configured to removethe exhaust gas G used to cool each of the line cards 332 via asubstantially parallel flow circuit.

Although the intake flow pathway 321 is shown and described as receivingan intake gas to be supplied to the interior region 313 of the chassis310, in other embodiments, an exhaust gas can flow from the interiorregion 313 out of the chassis 310 via the intake flow pathway 321.Although the exhaust gas is shown and described as flowing withinexhaust flow pathway 326 out of the chassis 310, in other embodiments,intake gas can flow into the interior region 313 via the exhaust flowpathway 326. Similarly stated, in other embodiments, the chassis 310 andthe line cards 332 can collectively form an intake flow pathway withinwhich intake gas can flow.

FIGS. 4-9 show a data processing unit 400 according to an embodimenthaving an orthogonal midplane configuration. The data processing unit400 includes a chassis 410, a midplane 414 disposed within the chassis410, a first (i.e., rear) set of line cards 430 (see e.g., FIGS. 5-7)and a second (i.e., front) set of line cards 450 (see e.g., FIGS. 4, 6and 7). The chassis 410 includes an enclosure 412 that defines aninternal region 413 of the chassis 410. The midplane 414 is disposedwithin the internal region 413 such that the chassis 410 is divided intoa front portion 418 and a rear portion 419. The first set of line cards430 is disposed within the rear portion 419 of the chassis 410 in asubstantially horizontal orientation, and is coupled to the rear side ofthe midplane 414. The second set of line cards 450 is disposed withinthe front portion 418 of the chassis 410 in a substantially verticalorientation, and is coupled to the front side of the midplane 414. Inthis manner, the first set of line cards 430 is oriented substantiallyorthogonal to the second set of line cards 450. Similarly stated, inthis manner, the data processing unit 400 has an orthogonal midplaneconfiguration.

The first set of line cards 430 includes line cards 432. Similarly, thesecond set of line cards 450 includes line cards 452. Only a portion ofthe line cards 432 and the line cards 452 are identified in FIGS. 4-9for purposes of clarity. Each of the line cards 432, 452 can be anysuitable circuit card that can process, transmit and/or conveyelectronic and/or optical signals. For example, in some embodiments, theline cards 432, 452 can include a printed circuit board populated withone or more electronic circuits (e.g., modules, chips, integratedcircuit packages, etc.) configured to perform the functions of the dataprocessing unit 400. In some embodiments, for example, the line cards432, 452 can be configured to convert optical signals to and fromelectrical signals. In some embodiments, the line cards 432, 452 can beconfigured to transmit multiple signals associated with one or more datastreams to and from other line cards and/or other data processing units(not shown) within a communications network. In some embodiments, theline cards 432 can have a different design and/or perform differentfunctions than the line cards 452. In other embodiments, the line cards432 and the line cards 452 can have substantially the same design and/orperform substantially the same functions.

As shown in FIGS. 7 and 8, each of the line cards 432 has a first endportion 433, a second end portion 434, and a central portion 435therebetween. The first end portion 433 of each line card 432 and thesecond end portion 434 of each line card 432 are coupled to theenclosure 412 of the chassis 410 within the rear portion 419 of thechassis 410. In this manner, the line cards 432 are disposed within therear portion 419 of the chassis 410 in a substantially parallel andhorizontal arrangement. Similarly stated, the line cards 432 aredisposed within the chassis 410 such that a surface 444 of each linecard 432 is substantially parallel to the surface 444 of the adjacentline card 432. Moreover, the surface 444 of each line card 432 issubstantially horizontal relative to the support structure (e.g., thefloor) upon which the data processing unit 400 is disposed. Although theline cards 432 are disposed within the rear portion 419 of the chassis410 in a substantially parallel and horizontal arrangement, in otherembodiments, the line cards 432 can be disposed within the chassis 410in any suitable arrangement.

The central portion 435 of each line card 432 defines an opening 443. Asshown in FIGS. 6-8, the line cards 432 are disposed within the rearportion 419 of the chassis 410 such that the opening 443 of each linecard 432 is substantially aligned with the opening 443 of the adjacentline card 432. In this manner, as described in more detail below, theline cards 432 and the chassis 410 collectively form a third flowpathway 426. Although the third flow pathway 426 is shown as beingdefined primarily by the line cards 432 (e.g., the openings 443), inother embodiments, the chassis 410 can include one or more baffles,ducts and/or internal structures to define the third flow pathway 426.

As shown in FIG. 9, each of the line cards 452 has a first end portion472 and a second end portion 473. The line cards 452 are disposed withinthe front portion 418 of the chassis 410 in a substantially parallel andvertical arrangement. Similarly stated, the line cards 452 are disposedwithin the chassis 410 such that a surface of each line card 452 issubstantially parallel to the surface of the adjacent line card 452.Moreover, the surface of each line card 452 is substantially verticalrelative to the support structure (e.g., the floor) upon which the dataprocessing unit 400 is disposed. Although the line cards 452 aredisposed within the front portion 418 of the chassis 410 in asubstantially parallel and vertical arrangement, in other embodiments,the line cards 452 can be disposed within the chassis 410 in anysuitable arrangement.

As shown in FIGS. 4, 6 and 7, the front portion 418 of the chassis 410includes a first internal side wall 420 and a second internal side wall422. The first internal side wall 420 and the second internal side wall422 are each substantially parallel to each of the line cards 452 of thesecond set of line cards 450. Moreover, the first internal side wall 420and the second internal side wall 422 define an enclosure within whichthe second set of line cards 450 is disposed. In some embodiments, thefirst internal side wall 420 and/or the second internal side wall 422can include coupling members and/or portions (not shown), such as clips,brackets, slots, or the like, configured to retain and/or support theline cards 452 and/or any other components housed within the chassis410.

The enclosure 412 and the first internal side wall 420 collectivelydefine a first flow pathway 421. The enclosure 412 and the secondinternal side wall 422 collectively define a second flow pathway 423.Similarly stated, the chassis 410 defines the first flow pathway 421 andthe second flow pathway 423. Although the first flow pathway 421 and thesecond flow pathway 423 are shown as being defined substantiallyentirely by the chassis 410 (e.g., by the enclosure 412, the firstinternal side wall 420 and the second internal side wall 422) in otherembodiments, a chassis can define only a portion of a first flow pathwayand/or a portion of a second flow pathway. In yet other embodiments, achassis can define, only in part, a portion of a first flow pathwayand/or a portion of a second flow pathway.

The first flow pathway 421 extends within the chassis 410 between anintake region INT exterior to the chassis 410 (see e.g., FIGS. 4 and 7)and the first end portion 433 of each of the line cards 432. Moreparticularly, the chassis 410 is configured such that a first portion ofintake air G1 can flow from the intake region INT into the first flowpathway 421, as shown by the arrow OO in FIGS. 6 and 7. The chassis 410is configured such that the first portion of intake air G1 can exit thefirst flow pathway 421 and flow across the surface 444 of each line card432 from the first end portion 433 towards the central portion 435, asshown by the arrow PP in FIGS. 6-8. Similarly stated, the chassis 410 isconfigured such that the first portion of intake air G1 can exit thefirst flow pathway 421 and flow substantially parallel to the surface444 of each line card 432. In this manner, the chassis 410 is configuredto supply the first portion of intake air G1 to cool each of the linecards 432 via a substantially parallel flow circuit. In someembodiments, the chassis 410 is configured such that at least a portionof the first portion of intake air G1 can exit the first flow pathway421 and flow across the surface 444 of each line card 432 in a firstdirection substantially parallel to a longitudinal axis of the line card432.

The second flow pathway 423 extends within the chassis 410 between theintake region INT exterior to the chassis 410 and the second end portion434 of each of the line cards 432. More particularly, the chassis 410 isconfigured such that a second portion of intake air G2 can flow from theintake region INT into the second flow pathway 423, as shown by thearrow OO′ in FIGS. 6 and 7. The chassis 410 is configured such that thesecond portion of intake air G2 can exit the second flow pathway 423 andflow across the surface 444 of each line card 432 from the second endportion 434 towards the central portion 435, as shown by the arrow PP′in FIGS. 6-8. Similarly stated, the chassis 410 is configured such thatthe second portion of intake air G2 can exit the second flow pathway 423and flow substantially parallel to the surface 444 of each line card432. In this manner, the chassis 410 is configured to supply the secondportion of the intake air G2 to cool each of the line cards 432 via asubstantially parallel flow circuit. In some embodiments, the chassis410 is configured such that at least a portion of the second portion ofintake air G2 can exit the second flow pathway 423 and flow across thesurface 444 of each line card 432 in a second direction substantiallyparallel to a longitudinal axis of the line card 432, and opposite thefirst direction.

As shown in FIGS. 7 and 8, the rear portion 419 of the chassis 410includes an upper fan tray 460 and a lower fan tray 462. The upper fantray 460 includes two fans or blowers 461 configured to produce (ordefine, at least in part) an airflow within the chassis 410. The lowerfan tray 462 includes two fans or blowers 463 configured to produce (ordefine, at least in part) an airflow within the rear portion 419 of thechassis 410. Similarly stated, the blowers 461 and 463 are configured toproduce an airflow within the chassis 410 such that the first portion G1and the second portion G2 of the intake air can flow within the firstflow pathway 421 and the second flow pathway 423, as described above.The blowers 461 and 463 further produce an airflow such that the exhaustair (i.e., the first portion G1 and the second portion G2 of the intakeair after flowing across a portion of the a line card 432) can flowwithin the exhaust flow pathway 426, as described below. Although theupper fan tray 460 and the lower fan tray 462 are each shown asincluding two distinct blowers (e.g., blowers 461 and 463,respectively), in other embodiments, the upper fan tray 460 and/or thelower fan tray 462 can include a single blower. In yet otherembodiments, the upper fan tray 460 and/or the lower fan tray 462 caninclude a blower having a dual impeller configuration. For example, insome embodiments, the blower 461 and/or the blower 463 can be the SFB196×109×33 mm series dual impeller blower produced by Delta Electronics,Inc.

As described above, the chassis 410 and the line cards 432 collectivelydefine a third flow pathway 426 (see e.g., FIG. 7) such that the exhaustair can flow between the central portion 435 of each line card 432 andan exhaust region EXH exterior to the chassis 410 (see e.g., FIGS. 6 and7). As shown in FIGS. 7 and 8, the blowers 461 of the upper fan tray 460are configured to produce an airflow within the third flow pathway 426such that a portion of the exhaust air flows in a first direction (e.g.,upward) within the third flow pathway 426 and into the blowers 461, asshown by the arrow QQ. The exhaust air exits the blowers 461, as shown,by the arrows SS and SS′ and flows to the exhaust region EXH via theexhaust openings 407 defined by the chassis 410 (see e.g., FIGS. 5 and6). The blowers 463 of the lower fan tray 462 are configured to producean airflow within the third flow pathway 426 such that a portion of theexhaust air flows in a second direction (e.g., downward) within thethird flow pathway 426, as shown by the arrow RR. The exhaust air exitsthe blowers 463, as shown, by the arrows TT and TT′ and flows to theexhaust region EXH via the exhaust openings 407 defined by the chassis410.

Thus, the chassis 410 is configured such that the exhaust air can flowwithin the third flow pathway 426 from the central portion 435 of eachline card 432, as shown by the arrows QQ and RR in FIGS. 7 and 8. Saidanother way, the chassis 410 is configured such that the exhaust air canflow from a region proximate the surface 444 of each line card 432 intothe third flow pathway 426, as shown by the arrows QQ and RR in FIGS. 7and 8. Similarly stated, the chassis 410 is configured such that theexhaust air can flow from the central portion 435 of the each line card432 in a direction substantially orthogonal to the surface 444 of eachline card 432. In this manner, the chassis 410 is configured to removethe air used to cool each of the line cards 432 via a substantiallyparallel flow circuit.

As shown in FIGS. 4, 8 and 9, the front portion 418 of the chassis 410includes an upper fan tray 466 and a lower fan tray 464. The upper fantray 466 and the lower fan tray 464 each include fans or blowersconfigured to produce (or define, at least in part) an airflow withinthe chassis 410. The blowers (not identified in FIGS. 4 and 9) areconfigured produce an airflow such that a third portion G3 of intake aircan flow across the second set of line cards 450, as described below.The upper fan tray 466 and/or the lower fan tray 464 can include anynumber and/or type of blowers. In some embodiments, for example, theupper fan tray 466 can include a different blower configuration than thelower fan tray 464. In other embodiments, the upper fan tray 466 and/orthe lower fan tray 464 can include blowers different from the blowers461 and 463 described above. In yet other embodiments, the blowersincluded in the upper fan tray 466 and the lower fan tray 464 can be thesame as the blowers 461 and 463 described above.

As shown in FIGS. 4 and 9, the first internal side wall 420 and thesecond internal side wall 422 collectively define a fourth flow pathway455. The fourth flow pathway 455 extends within the chassis 410 betweenthe intake region INT exterior to the chassis 410 and the first endportion 472 of each of the line cards 452 from the second set of linecards 450. More particularly, the chassis 410 is configured such that athird portion G3 of intake air can flow from the intake region INT intothe fourth flow pathway 455, as shown by the arrow UU in FIG. 9. Thechassis 410 is configured such that the third portion G3 of intake aircan flow via the blowers in the lower fan tray 464 from the fourth flowpathway 455 and across the surface of each line card 452. Moreparticularly, the chassis 410 is configured such that the third portionG3 of the intake air can flow across each line card 452 from the firstend portion 472 towards the second end portion 473, as shown by thearrow VV in FIG. 9. Similarly stated, the chassis 410 is configured suchthat the third portion G3 of intake air can flow substantially parallelto a surface of each line card 452. In this manner, the chassis 410 isconfigured to supply the third portion G3 of the intake air to cool eachof the line cards 452 via a substantially parallel flow circuit.

Moreover, the fourth flow pathway 455 is substantially isolated from thefirst flow pathway 421 and the second flow pathway 423. In this manner,the quantity of airflow (e.g., mass flow rate, volumetric flow rate orthe like) within the fourth flow pathway 455 is independent of thequantity of airflow within the first flow pathway 421 and/or the secondflow pathway 423. Said another way, the flow rate of cooling airsupplied to the second set of line cards 450 is independent of the flowrate of cooling air supplied to the first set of line cards 430. In thismanner, the flow rate of cooling air supplied the front portion 418 ofthe chassis 410 can be adjusted without adjusting (e.g., diverting airfrom or to) the flow rate of cooling air supplied to the rear portion419 of the chassis 410.

As shown in FIG. 9, the chassis 410 includes a third internal side wall454 substantially parallel to the top portion of the enclosure 412. Theenclosure 412 and the third internal side wall 454 collectively define afifth flow pathway 456 such that the exhaust air can flow between thesecond end portion 473 of each line card 452 and an exhaust region EXHexterior to the chassis 410. More particularly, the chassis 410 isconfigured such that the third portion G3 of intake air can flow via theblowers in the upper fan tray 466 from the second end portion 473 ofeach line card 452 to the exhaust region EXH, as shown by the arrow WWin FIG. 9. The third portion G3 of the intake air is conveyed from theinternal region 413 of the chassis 410 via the exhaust openings 408defined by the chassis 410 (see e.g., FIG. 5).

Moreover, the fifth flow pathway 456 is substantially isolated from thethird flow pathway 426. Similarly stated, the exhaust flow path of thefront portion 418 (i.e., the fifth flow pathway 456) is fluidicallyisolated from the exhaust flow path of the rear portion (i.e., the thirdflow pathway 426). In this manner, the quantity of airflow (e.g., massflow rate, volumetric flow rate or the like) within the fifth flowpathway 456 is independent of and/or does not influence the quantity ofairflow within the third flow pathway 426. Similarly stated, in thismanner, a restriction, impedance or the like within the fifth flowpathway 456 has no substantial effect on the flow rate of exhaust airwithin the third flow pathway 426.

As shown in FIGS. 4 and 5, the lower portion of the chassis 410 containsa set of power supplies 402. The front portion 418 of the chassis 410defines an inlet opening 403 associated with each of the power supplies402. As shown in FIG. 5, the rear portion 419 of the chassis 410 definesan outlet opening 404 associated with each of the power supplies 402. Asshown in FIG. 9, the chassis 410 further defines a flow pathway 405through which cooling air can flow to cool the power supplies 402. Inoperation, cooling air can flow through the inlet openings 403, withinthe flow pathway 405, and out of outlet openings 404, as shown by thearrow XX, to cool the power supplies 402.

Although the openings 443 defined by the line cards 432 are shown asbeing substantially rectangular, in other embodiments, the openings 443can have any suitable shape. Although the openings 443 are shown asbeing defined solely by the line cards 432, in other embodiments, anopening can be bounded by a portion of a line cards and a side wall ofthe chassis. Although the line cards 432 are each shown as defining asingle opening 443, in other embodiments, a line card can define anynumber of openings and/or flow pathways.

For example, FIG. 10 shows a portion of a data processing unit 500according to another embodiment having an orthogonal midplaneconfiguration. The data processing unit 500 is similar to the dataprocessing unit 400 in that the chassis 510 defines multiple intake airflow pathways similar to the flow pathways 421, 423 and 455 describedabove. The data processing unit 500 differs from the data processingunit 400, however, in that the chassis 510 and the first set of linecards 530 define multiple exhaust flow pathways 526, as described inmore detail below.

The data processing unit 500 includes a chassis 510, a midplane (notshown in FIG. 10) disposed within the chassis 510 that divides thechassis 510 into a front portion 518 and a rear portion 519. The dataprocessing unit 500 includes a first (i.e., rear) set of line cards 530disposed within the rear portion 519 and a second (i.e., front) set ofline cards (not shown) disposed within the front portion 518. Thechassis 510 includes an enclosure 512 that defines an internal region513 of the chassis 510.

The first set of line cards 530 includes line cards 532. Each of theline cards 532 can be any suitable circuit card of the types shown anddescribed herein, that can process, transmit and/or convey electronicand/or optical signals. Each of the line cards 532 has a first endportion 533, a second end portion 534, and a central portion 535therebetween. As shown in FIG. 10, the first end portion 533 of eachline card 532 and the second end portion 534 of each line card 532 arecoupled to the enclosure 512 of the chassis 510 within the rear portion519 of the chassis 510. In this manner, the line cards 532 are disposedwithin the rear portion 519 of the chassis 510 in a substantiallyparallel and horizontal arrangement. Although the line cards 532 aredisposed within the rear portion 519 of the chassis 510 in asubstantially parallel and horizontal arrangement, in other embodiments,the line cards 532 can be disposed within the chassis 510 in anysuitable arrangement.

Each of the line cards 532 includes a support member 541 and a printedcircuit board 540 coupled to the support member 541. The support member541 is configured to enhance the strength and/or rigidity of the linecard 532. For example, in some embodiments, the support member 541 canbe a metallic member that includes coupling portions (not shown in FIG.11) to facilitate the coupling between the line card 532 and the chassis510. In other embodiments, the support member 541 can enhance otherproperties of the line card 532, such as for example, the thermalconductivity of the line card 532, the electromagnetic interference(EMI) noise characteristics of the line card 532 and/or the like.

The printed circuit board 540 can be any suitable printed circuit boardupon which electrical components (i.e., signal processors, connectors,or the like) can be interconnected. More particularly, as shown in FIG.11, the printed circuit board 540 includes a surface 544 upon whichelectrical circuits 542 coupled and/or interconnected to perform thedata processing functions of the line card 532. The electrical circuits542 can be any suitable electrical circuit and/or component, such as,for example, a signal process, an application-specific integratedcircuit (ASIC) and/or the like. Moreover, the printed circuit board 540connectors 539 are configured to couple the line card 532 to themidplane.

As shown in FIG. 11, the support member 541 of each line card 532defines four openings 543. As shown in FIG. 10, the line cards 532 aredisposed within the rear portion 519 of the chassis 510 such that theopenings 543 of each line card 532 are substantially aligned with theopenings 543 of the adjacent line card 532. In this manner, the linecards 532 and the chassis 510 collectively form a series of exhaust flowpathways 526. Although the exhaust flow pathways 526 are shown as beingdefined primarily by the line cards 532 (e.g., the openings 543), inother embodiments, the chassis 510 can include one or more baffles,ducts and/or internal structures to define portions of the exhaust flowpathways 526.

As shown in FIG. 10, the rear portion 519 of the chassis 510 includes anupper fan tray 560 and a lower fan tray 562, each including blowersconfigured to produce an airflow within the chassis 510. Thus, theblowers draw cooling air into the rear portion 519 of the chassis fromthe first end portion 533 and the second end portion 534 of each linecard 532 as shown by the arrows AAA and BBB, respectively, in FIG. 11.In this manner, the cooling air can flow across the surface 444 of eachline card 432 from the second end portion 434 towards the exhaust flowpathways 526. Similarly stated, the chassis 410 is configured such thatthe intake air can flow in a direction substantially parallel to thesurface 444 of each printed circuit board 540. After flowing across eachline card 532, the blowers draw the exhaust air from the rear portion519 of the chassis 510 to an exhaust region outside of the chassis 510via the exhaust flow pathways 526, in a similar manner as describedabove with reference to the data processing unit 400. More particularly,as described above, the exhaust gas flows within the exhaust flowpathways 526 in a direction substantially orthogonal to the direction ofthe flow of the intake air. Similarly stated, the exhaust gas flowswithin the exhaust flow pathways 526 in a direction substantiallyorthogonal to the surface 544 of the line card 532.

Although shown as being substantially square, the openings 543 can haveany suitable size and/or shape. For example, in some embodiments, theopenings can be substantially rectangular and/or can have an areabetween approximately four percent and sixteen percent of the surfacearea of the line card 532. In other embodiments, the openings can havean area as much as twenty percent of the surface area of the line card532. In yet other embodiments, the openings 543 can be a series ofperforations defined by the support member 541.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Where methods and/or schematics described above indicatecertain events and/or flow patterns occurring in certain order, theordering of certain events and/or flow patterns may be modified. Whilethe embodiments have been particularly shown and described, it will beunderstood that various changes in form and details may be made.

For example, although the first internal side wall 420 and the secondinternal side wall 422 are shown as being substantially planar, in otherembodiments, the first internal side wall 420 and the second internalside wall 422 can have any suitable shape. In some embodiments, forexample, an internal side wall can have a curved shape.

Although the chassis shown and described above define various flowpathways being identified as intake flow pathways (e.g., the first flowpathway 421 and the second flow pathway 423) and exhaust flow pathways(e.g., the exhaust flow pathway 426), in other embodiments, thedirection of gas flow within the chassis can be reversed. For example,although the data processing unit 400 is shown and described asreceiving intake air from the front portion 418 of the chassis andproducing an exhaust flow proximate the rear portion 419 of the chassis,in other embodiments, a data processing unit can receive intake air fromthe rear portion of the chassis and produce an exhaust flow proximatethe front portion of the chassis.

Although the line card 432 is shown as defining an opening 443 disposedtowards the rear portion of the line card 432 (i.e., the portion of theline card 432 opposite the midplane 414), in other embodiments, a linecard can define one or more openings at any location of the line card.For example, in some embodiments, a line card can define an opening atportion of the line card proximate the midplane.

Although the line cards are described herein in some embodiments asbeing configured to process, transmit and/or convey optical signals(e.g., converting an optical signal into an electrical signal), in otherembodiments, a line card need not be configured to receive, process,transmit and/or convey optical signals. For example, in someembodiments, a line card (such as, for example, line card 532) can beconfigured to receive, process, transmit and/or convey electricalsignals (i.e., voltage signals, current signals or the like).

Although various embodiments have been described as having particularfeatures and/or combinations of components, other embodiments arepossible having a combination of any features and/or components from anyof embodiments as discussed above. For example, in some embodiments, adata processing unit can define a flow pathway configured to direct anexhaust flow out of a central portion of the chassis (similar to theflow pathway 226) and a flow pathway configured to direct exhaust flowout of an end portion of the chassis (similar to the flow pathway 326).

1. An apparatus, comprising: a plurality of line cards, each line cardfrom the plurality of line cards defining an opening and having asurface, a first end portion and a second end portion; and a chassisdefining, at least in part, a portion of a first intake flow pathway anda portion of a second intake flow pathway, an interior region of thechassis configured to contain the plurality of line cards such that theopening of each line card from the plurality of line cards collectivelydefines, at least in part, a portion of an exhaust flow pathway, thechassis configured such that a first gas can flow within the firstintake flow pathway between an intake region outside of the chassis andthe first end portion of each line card from the plurality of line cardssuch that a portion of the first gas flows across the surface of eachline card from the plurality of line cards in a first direction, thechassis configured such that a second gas can flow within the secondintake flow pathway between the intake region outside of the chassis andthe second end portion of each line card from the plurality of linecards such that a portion of the second gas flows across the surface ofeach line card from the plurality of line cards in a second direction,the second direction opposite the first direction, the chassis and theplurality of line cards collectively configured such that a mixture ofthe first gas and the second gas can flow within the exhaust flowpathway from the interior region of the chassis to an exhaust regionoutside of the chassis such that a first portion of the mixture of thefirst gas and the second gas flows in a third direction substantiallyorthogonal to the first direction and a second portion of the mixture ofthe first gas and the second gas flows in a fourth direction, the fourthdirection opposite the third direction.
 2. The apparatus of claim 1,wherein: the intake region is proximate a front portion of the chassis;and the exhaust region is proximate a rear portion of the chassis. 3.The apparatus of claim 1, further comprising: a midplane disposed withinthe chassis such that the midplane divides the chassis into a frontportion and a rear portion, the plurality of line cards disposed withinthe rear portion of the chassis, the chassis configured such that thegas flows within the front portion of the chassis when the first gasflows within the first intake flow pathway.
 4. The apparatus of claim 1,wherein the plurality of line cards is a first plurality of line cards,the apparatus further comprising: a midplane disposed within the chassissuch that the midplane divides the chassis into a front portion and arear portion, the first plurality of line cards disposed within the rearportion of the chassis, the chassis configured to contain a secondplurality of line cards within the front portion of the chassis, thechassis is configured such that the first gas flows within the frontportion of the chassis isolated from the second plurality of line cardswhen the first gas flows within the first intake flow pathway.
 5. Theapparatus of claim 1, wherein: each line card from the plurality of linecards includes a central portion disposed between the first end portionand the second end portion, the central portion of each line carddefining the opening of each line card from the plurality of line cardssuch that the opening of each line card from the plurality of line cardsis disposed approximately an equal distance from the first end portionand the second end portion.
 6. The apparatus of claim 1, furthercomprising: a midplane disposed within the chassis such that themidplane divides the chassis into a front portion and a rear portion,the plurality of line cards disposed within the rear portion of thechassis, the chassis configured such that the first gas flows within thefront portion of the chassis in a fifth direction substantially parallelto the surface of each line card from the plurality of line cards, thefifth direction substantially orthogonal to the first direction.
 7. Theapparatus of claim 1, further comprising: a first fan tray including atleast one fan in fluid communication with the exhaust flow pathway; anda second fan tray including at least one fan in fluid communication withthe exhaust flow path, the plurality of line cards disposed within thechassis between the first fan tray and the second fan tray.
 8. Anapparatus, comprising: a chassis defining, at least in part, a portionof a first intake flow pathway and a portion of a second intake flowpathway; a midplane disposed within the chassis such that the midplanedivides the chassis into a front portion and a rear portion; a firstline card disposed within the rear portion of the chassis, the firstline card having a first end portion, a second end portion and a centralportion between the first end portion and the second end portion; and asecond line card disposed within the rear portion of the chassis, thesecond line card having a first end portion, a second end portion and acentral portion between the first end portion of the second line cardand the second end portion of the second line card, the central portionof the first line card, the central portion of the second line card andthe chassis collectively defining, at least in part, a portion of anexhaust flow pathway, the chassis configured such that a first gas canflow within the first intake flow pathway from an intake region exteriorto the chassis to the first end portion of the first line card and thefirst end portion of the second line card, the chassis configured suchthat a second gas can flow within the second intake flow pathway fromthe intake region to the second end portion of the first line card andthe second end portion of the second line card, the chassis and thefirst line card collectively configured such that a first portion of amixture of the first gas and the second gas can flow in a firstdirection within the exhaust flow pathway from the rear portion of thechassis to an exhaust region exterior to the rear portion of thechassis, the chassis and the second line card collectively configuredsuch that a second portion of the mixture of the first gas and thesecond gas can flow in a second direction within the exhaust flowpathway from the rear portion of the chassis to the exhaust region, thesecond direction opposite the first direction.
 9. The apparatus of claim8, wherein: the chassis is configured such that a first portion of thefirst gas flows across a surface of the first line card in a thirddirection and a second portion of the first gas flows across a surfaceof the second line card in the third direction; the chassis isconfigured such that a first portion of the second gas flows across thesurface of the first line card in a fourth direction and a secondportion of the second gas flows across the surface of the second linecard in the fourth direction, the fourth direction opposite the thirddirection, the third direction substantially orthogonal to the firstdirection.
 10. The apparatus of claim 8, wherein: the central portion ofthe first line card and the central portion of the second line card eachdefine an opening that collectively defines, in part, the portion of theexhaust flow pathway.
 11. The apparatus of claim 8, wherein the firstdirection and the second direction are each substantially orthogonal toa surface of the first line card.
 12. The apparatus of claim 8, wherein:the chassis is configured such that a portion of the first gas flowswithin a portion of the first intake flow pathway in the front portionof the chassis in a third direction substantially parallel to thesurface the first line card, and the portion of the first gas flowsacross a surface of the first line card in a fourth directionsubstantially parallel to the surface the first line card, the fourthdirection different from the third direction, the fourth direction andthe third direction substantially orthogonal to the first direction. 13.The apparatus of claim 8, further comprising: a first fan tray includingat least one fan in fluid communication with the exhaust flow pathway;and a second fan tray including at least one fan in fluid communicationwith the exhaust flow path, the first line card and the second line carddisposed within the chassis between the first fan tray and the secondfan tray.
 14. An apparatus, comprising: a chassis defining an interiorregion, the chassis defining, at least in part, a portion of an intakeflow pathway; a first fan disposed within the interior region; a secondfan disposed within the interior region; and a plurality of line cardsdisposed within the interior region of the chassis between the first fanand the second fan, each line card from the plurality of line cardshaving a surface and defining an opening, the chassis configured suchthat a gas can flow within the intake flow pathway between an intakeregion exterior to the chassis and the interior region of the chassis,and across the surface of each line card from the plurality of linecards in a first direction, the first direction substantially parallelto the surface of each line card, the chassis and the plurality of linecards collectively defining a portion of an exhaust flow pathwaysubstantially aligned with the opening of each line card from theplurality of line cards, the chassis and the plurality of line cardscollectively configured such that (1) a first portion of the gas canflow within the portion of the exhaust flow pathway in a seconddirection from the interior region of the chassis, through the first fanand to an exhaust region exterior to the chassis, (2) the seconddirection substantially orthogonal to the surface of each line card fromthe plurality of line cards, and (3) a second portion of the gas canflow within the portion of the exhaust flow pathway in a third directionfrom the interior region of the chassis, through the second fan and tothe exhaust region, the third direction opposite the second direction.15. The apparatus of claim 14, wherein: the gas is a first gas; theintake flow pathway is a first intake flow pathway; the chassis defines,at least in part, a portion of a second intake flow pathway, the chassisconfigured such that a second gas can flow within the third secondintake flow pathway between the intake region exterior to the chassisand the interior region of the chassis such that the second gas flowsacross the surface of each line card from the plurality of line cards ina fourth direction, the fourth direction substantially opposite thefirst direction; and the chassis and the line card collectivelyconfigured such that the first gas and the second gas can flow withinthe portion of the exhaust flow pathway between the interior region ofthe chassis and the exhaust region exterior to the chassis.
 16. Theapparatus of claim 14, further comprising: a midplane disposed withinthe chassis such that the midplane divides the chassis into a frontportion and a rear portion, the front portion of the chassis beingbetween the intake region and the interior region, the rear portion ofthe chassis being between the exhaust region and the interior region.17. The apparatus of claim 14, wherein a central portion of each linecard from the plurality of line cards defines the opening.
 18. Theapparatus of claim 14, wherein the plurality of line cards is a firstplurality of line cards, the apparatus further comprising: a midplanedisposed within the chassis such that the midplane divides the chassisinto a front portion and a rear portion, the first plurality of linecards disposed within the rear portion of the chassis, the chassisconfigured to receive a second plurality of line card within the frontportion of the chassis, the chassis is configured such that the gasflows within the front portion of the chassis isolated from the secondplurality of line cards when the gas flows within the intake flowpathway.
 19. The apparatus of claim 14, further comprising: a midplanedisposed within the chassis such that the midplane divides the chassisinto a front portion and a rear portion, the plurality of line cardsdisposed within the rear portion of the chassis, the chassis configuredsuch that the gas flows within the front portion of the chassis in afourth direction substantially parallel to the surface of each line cardfrom the plurality of line cards, the fourth direction different fromthe first direction.